Guidance document
In 2020, Laikre, Hoban and colleagues outlined an approach to assess genetic diversity status and trends without requiring any genetic data (e.g. DNA sequence) , using ‘genetic indicators’. The indicators were developed in response to a recognized gap in reporting to the U.N. Convention on Biological Diversity (CBD). There was a need for tools to report on ‘genetic erosion’ and ‘safeguarding’ or ‘maintaining’ genetic diversity, within and among populations of species. The indicators allow a fairly standardized and rapid way to assess whether a species is likely to be losing or has lost genetic diversity by quantifying critical aspects of demography that generally correlate to genetic diversity: (1) the size of each population (number of adult individuals), and (2) the geographic range or number of populations relative to historic conditions. (A third indicator on genetic knowledge/ genetic studies has also been proposed, and will be discussed below).
The logic behind these indicators is simple. (1) Small populations lose genetic diversity, and very small populations lose genetic diversity very quickly (Frankham 2021). (2) Loss of populations can result in loss of unique genetic adaptations (Exposito Alonso et al 2022). So, measuring population size and loss of populations is a fairly good proxy or summary of genetic diversity status, without ever measuring the DNA diversity itself.